artery

artery, blood vessel that conveys blood away from the heart. Except for the pulmonary artery, which carries deoxygenated blood from the heart to the lungs, arteries carry oxygenated blood from the heart to the tissues. The largest arterial trunk is the aorta, branches of which divide and subdivide into ever-smaller tubes, or arterioles, until they terminate as minute capillaries, the latter connecting with the veins (see circulatory system). Other important arteries are the subclavian and brachial arteries of the shoulder and arm, the carotid arteries that lead to the head, the coronary arteries that nourish the heart itself, and the iliac and femoral arteries of the abdomen and lower extremities. The walls of the large arteries have three layers: a tough elastic outer coat, a layer of muscular tissue, and a smooth, thin inner coat. Arterial walls expand and contract with each heartbeat, pumping blood throughout the body. The pulsating movement of blood, or pulse, may be felt where the large arteries lie near the body surface.